What the hell is " critical listening " ? Critiquing the music ? The system ? 
For me, in the context of audiophiling, I describe "critical listening" as listening for specific characteristics of the sound being produced by a system. Usually, this is what I do when I'm testing out new gear, trying new room treatment designs, setting up a new system, etc.
"Casual listening" is having music playing without any attention to the sonics; other people in the room, not nessarily sitting in the sweet spot, etc. Maybe I'm surfing AC or doing something else, although that probably counts as "background music" and not really listening.
"Listening for enjoyment" is having the listening room all to myself, no distractions, and just sitting in the sweetspot to enjoy some music. If the music deserves "critiquing", it usually gets the boot quickly and I move on to something else...
Since moving to my new house, with the "man-room" all to myself, I get in about 1 CD of listening for enjoyment every day. Before that, it was mostly casual listening, with 20-30 minutes of listening for enjoyment every few days...